Optical Sensor-Based Nitrogen Fertilization in Grain Sorghum in Arkansas.

Optical Sensor-Based Nitrogen Fertilization in Grain Sorghum in Arkansas Ground-based active-optical (GBAO) crop sensors have become an effective tool to improve nitrogen (N) use efficiency and to predict yield early in the growing season, particularly for grass crops. The objective of this study was to evaluate the relative performance of a Greenseeker® and a Crop Circle® sensor in grain sorghum. Chlorophyll readings were also collected on a weekly basis. Nitrogen rate experiments (27, 54, 81,108,135 kg ha-1) were established at several locations in Arkansas during 2012 and 2013. Sensors readings were collected weekly from grow stages 3 to 9. Preliminary results will be discussed.